Hm, I'm finding it hard to get units with good offense in Hoshido. Just completed chapter 11 and I asked myself midway through what Hinoka and Subaki even were doing there. When the enemy has over 20 HP, it just doesn't cut it to double with 4 damage unless you're a ninja or Felicia with debuff riders on it. Also looking at you, there, Rinkah. Good defense on her, though. Can take an axe to the face better than anyone.
Do the Pegasus riders just suck in this game or am I just being unlucky?
I found them to be pretty meh. Subaki is kinda meh since he has no speed and hilariously high defense for a class that's pretty frail to begin with. They were mostly relegated to staff bots by the end of my games.
Spear Master is a better class if you're planning on continue using them since they get S rank in lances and a critical bonus which is always nice.